The final regulations for coal-powered plants, released Wednesday, stipulate they can emit no more than 420 tonnes of greenhouse gases per gigawatt hour of electricity generated.

This number is significantly higher than the 375 tonnes per gigawatt hour Kent proposed in earlier draft regulations released in August.

While admitting the new rules are “at the high end” of the 360 to 425 tonne per gigawatt hour range he considered, Kent said the decision was made to avoid putting the “consuming public at risk of inadequate power supply.”

“That 375 … would have been applicable only if, in the coal-fired electricity sector, plants operated at a steady productivity,” Kent said. “In reality, plants go up and down in the generation of energy depending on demand.”

Power plants simply could not satisfy the demand for power and meet more stringent emissions regulations at the same time, Kent said.

Critics lined up to slam the difference between the draft and final regulations.

The Sierra Club accused Kent of further relaxing “already grossly inadequate regulations.”

“Kent’s announcement is a either a bad joke or an insult to the intelligence of Canadians. It’s amazing he can make these announcements with a straight face,” John Bennett, executive director of Sierra Club Canada, said in a news release.

The Pembina Institute said coal-fired power plants represent seven of Canada’s top 10 polluters.

“Feasible alternatives exist today, making the electricity sector a win-win for progress on our climate and clean-air commitments,” said policy analyst P.J. Partington.

“Instead of seizing this opportunity, the federal government has drastically weakened its own regulations, making them only half as effective over their first ten years compared to what the government had originally proposed.”

Kent, who announced the new regulations in Saskatoon, said the new rules find the balance between emissions reductions and Canada’s “very fragile” economic recovery.

“I think the suggestion the regulations have been softened or weakened is a misperception,” he said.

Kent said more than 5,000 submissions were made after the first draft of the regulations were published in the Canada Gazette one year ago, adding that some industry players were lobbying for targets well above 425 tonnes per gigawatt hour.

The new regulations also stipulate that coal-powered plants must be shut down after 50 years of operation. It was 45 years in previous draft regulations.

Power stations commissioned before 1975 will have to shut down after 50 years or at the end of 2019, Kent said, whichever comes earlier. Units commissioned between 1975 and 1986 must be shuttered after 50 years or at the end of 2029, whichever comes first.

Kent said that by 2019, three Canadian coal-fired plants would shut down. By 2029, he said, some 23 units are will cease operations.

Guy Bruce, vice president of planning for SaskPower, said the electrical industry and various provinces came together to lobby Environment Canada and the Prime Minister’s Office to relax the initial proposed regulations.

“We are pleased that our feedback has been heard,” Bruce said. “We see the changes announced today as very positive, especially the proposed change to end of life for coal units from 45 to 50 years and the change in performance standard from 375 to 420 tonnes per gigawatt hour.”

Coal-fired power plants account for 11 per cent of Canada’s total greenhouse gas emissions, and 77 per cent of emissions from the power generation sector.

While more lenient than expected, Kent said the new rules are nothing to scoff at and are helping put Canada on track to meet the emissions reduction targets committed to at the Copenhagen summit.

“This equals a cumulative reduction in emissions of about 214 megatonnes in the first 21 years,” Kent said. “That’s equivalent to removing some 2.6 million vehicles from the road every year during this period.”